class Solution {//leetcode695——岛屿面积
private:
    int dx[4]={0,0,1,-1};
    int dy[4]={1,-1,0,0};
    void bfs(vector<vector<int>>& grid,int i,int j){
        vis[i][j]=true;
        priority_queue<pair<int,int>> que;
        que.push({i,j});
        while(!que.empty()){
            auto [a,b]=que.top();
            que.pop();
            for(int k=0;k<4;k++){
                int x=a+dx[k];
                int y=b+dy[k];
                if(x>=0&&x<m&&y>=0&&y<n&&vis[x][y]==false&&grid[x][y]==1)
                {
                    que.push({x,y});
                    vis[x][y]=true;
                }
            }
            path++;
        }
        ret=max(ret,path);
    }
public:
    int maxAreaOfIsland(vector<vector<int>>& grid) {
        m=grid.size(),n=grid[0].size();
        vis.resize(m,vector<bool>(n,false));
        for(int i=0;i<m;i++){
            for(int j=0;j<n;j++){
                if(grid[i][j]==1&&vis[i][j]==false){
                    path=0;
                    bfs(grid,i,j);
                }
            }
        }
        return ret;
    }
private:
    int ret=0;
    int path=0;
    vector<vector<bool>> vis;
    int m=0;
    int n=0;
};